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Topic: GZK paradox

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A paradox is an apparently true statement that seems to lead to a logical self-contradiction, or to a situation that contradicts common intuition.
Thus, the paradox of Frederic's birthday in The Pirates of Penzance establishes the surprising fact that a person may be more than N years old on his Nth birthday.
Elevator paradox: Elevators can seem to be mostly going in one direction, as if they were being manufactured on the roof, and disassembled in the basement.
www.teachersparadise.com /ency/en/wikipedia/p/pa/paradox.html   (1319 words)

For example, the Birthday paradox is more of a surprise than a paradox, while the resolution of Curry's paradox is still a matter of contention.
Paradox of hedonism: When one pursues happiness itself, one is miserable; but, when one pursues something else, one achieves happiness.
Low birth weight paradox: low birth weight babies have a higher mortality rate, babies of smoking mothers have lower average birth weight, babies of smoking mothers have a higher mortality rate, but low birth weight babies of smoking mothers have a lower mortality rate than other low birth weight babies.
www.guajara.com /wiki/en/wikipedia/p/pa/paradox.html   (1541 words)

 Learn more about Paradox in the online encyclopedia.   (Site not responding. Last check: 2007-10-13)
Raven paradox (or Hempel's Ravens): Observing a red apple increases the likelihood of all ravens being fl.
Simpson's paradox: An association in sub-populations may be reversed in the population.
A professional organization once found that economists with a PhD actually had a lower average salary than those with a BS - but this was found to be due to the fact that those with a PhD worked in academia, where salaries are generally lower.
www.onlineencyclopedia.org /p/pa/paradox.html   (1388 words)

A paradox is a statement that seems to lead to a logical self-contradiction, or to a situation that contradicts common intuition.
Raven paradox: Observing a red apple increases the likelihood of all ravens being fl.
Unexpected hanging paradox: The day of the hanging will be a surprise, so it can't happen at all.
www.ebroadcast.com.au /lookup/encyclopedia/pa/Paradox.html   (587 words)

 Paradox   (Site not responding. Last check: 2007-10-13)
A paradox is an apparently true statement or group of statements that seems to lead to a contradiction or to a situation that defies intuition.
Paradoxes which are not based on a hidden error generally happen at the fringes of context or language, and require extending the context (or language) to lose their Paradox quality.
Elevator paradox: Elevators can seem to be mostly going in one direction, as if they were being manufactured in the middle of the building and being disassembled on the roof and basement.
paradox.mindbit.com   (2272 words)

 Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal
While many physical paradoxes have accepted resolutions that make them little more than curiosities, others may defy resolution and be the result of an inadequate interpretation of the theory, an assumption about the physical world that is violated, or an indication that the theory inadequately describes the conditions.
This paradox was sometimes used to argue that a homogeneous and isotropic universe as required by the cosmological principle was necessarily finite in extent, but it turns out that there are ways to relax the assumptions in other ways that admit alternative resolutions.
These paradoxes are sometimes seen as relating to Zeno's paradoxes which all deal with the physical manifestations of mathematical properties of continuum, infinitesimals, and infinities often associated with space and time.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=physical_paradox   (2320 words)

 Greisen-Zatsepin-Kuzmin limit
The Greisen-Zatsepin-Kuzmin limit (GZK limit) is a theoretical upper limit on the energy of cosmic rays from distant sources.
This limit was computed in 1966 by Kenneth Greisen[?], Vadem Kuzmin[?] and Georgi Zatsepin[?], based on interactions between the cosmic ray and the cosmic microwave background radiation predicted by special relativity.
As of 2003, a number of cosmic ray experiments such as GLAST[?] and the Pierre Auger Observatory[?] are now planned which are intended to confirm or deny the correctness of the earlier observations.
www.ebroadcast.com.au /lookup/encyclopedia/gz/GZK_limit.html   (235 words)

 gzk paradox and expanding universe Text - Physics Forums Library
First, re supernovae 'accelerating away from us': the 'high-z' supernovae (SN) which provide evidence for the 'acceleration' are ~5 to 10 billion light years away (well, more accurately, the light which we now see from them has travelled for 5 to 10 billion years to get to us).
Then the GZK limit (http://en.wikipedia.org/wiki/GZK_paradox): based on the density of CMBR photons (~400 per cubic centimetre), cosmic ray protons with an energy of ~>50 EeV (1 EeV = 1018 eV) should only be able to travel ~<100 Mly before they collide with a CMBR photon and produce lots of pions.
But the size of the quarks only determines the chance of a collision - not the outcome of the collision - assuming the number of oxygen quarks is similar to the number of microwaves a cosmic ray proton encounters on its journey.
www.physicsforums.com /archive/index.php/t-21282.html   (658 words)

 The Ultimate Paradox Dog Breeds Information Guide and Reference
A paradox is an apparently true statement or group of statements that seems to lead to a contradiction or to a situation that defies intuition, such as "This statement is false".
Two-envelope paradox: Given two envelopes, one of which contains twice as much money as the other, the benefit seems always to lie in switching from one to the other.
Diamond-water paradox Why is water cheaper than diamonds, when humans need water to survive, not diamonds?
www.dogluvers.com /dog_breeds/Paradox   (2213 words)

 Paradoxes - curiouser.co.uk
Click HERE for a definition and an expanation of what exactly is meant by the term paradox.
Below is a list of paradoxes which you might be interest to research, some of which may be featured at curiouser.co.uk in due course.
St. Petersburg paradox: Can it be rational to refuse a small finite entry fee for a game with a possible infinite pay off?
www.curiouser.co.uk /paradoxes   (549 words)

 SU(5) GUT
It is not clear if the spectrum of this source extends high enough to pose a paradox comparable to the one indicated by Mk 501.
It is remarkable that in spite of these similarities at present there is only one mechanism that could resolve both paradoxes: a mechanism based on the single, however drastic, assumption of a violation of ordinary Lorentz invariance.
The corresponding result obtainable in the UHECRs context would imply that the GZK cutoff could be violated even for much smaller negative values of n...
www.valdostamuseum.org /hamsmith/SU5GUT.html   (5896 words)

 gzk paradox and expanding universe
Then the GZK limit: based on the density of CMBR photons (~400 per cubic centimetre), cosmic ray protons with an energy of ~>50 EeV (1 EeV = 10
Suppose the quarks in cosmic ray protons have a size i.e
Stecker has a good discussion of the GZK effect (see Section 2.2, starting on p7).
www.physicsforums.com /showthread.php?t=21282   (708 words)

 Paradoxes Resolved, Origins Illuminated - Antigravity Research
Imagine a negative-mass baseball fastened it to a coil spring; if you push the spring, the ball will accelerate back at you faster and faster until both it and your hand are crushed; pull and the ball will jump away until the spring (or your arm) breaks.
Part of the problem in assuming that Antimatter is not in balance with our known material universe is that we cannot step out of the forward motion of time, and the experiencer becomes an artifact in the experiment in that you cannot follow the particle/wave of antimatter into reverse time.
Well, parity would certainly solve a lot of problems by taking the wrinkles out of the folded brane space making our universe fairly uniform in nature with a vortical curve that was formed from the incoming graviton that may have originated from the flux fields around the reverse spin sister universe.
www.metaresearch.org /msgboard/topic.asp?TOPIC_ID=708&whichpage=2   (2979 words)

 Bad Astronomy and Universe Today Forum - Twin Paradox: Definitive Proof That It's SR?
This is known as the twins paradox, but it is a paradox only if one has the idea of absolute time at the back of one's mind.
Space and time are now dynamic quantities: when a body moves, or a force acts, it affects the curvature of space and time---and in turn the structure of space-time affects the way in which bodies move and forces act.
Lorentzian relativity for example uses a preferred reference frame, and time dilation would only be expected in the twin that is moving at a greater speed in that frame.
www.bautforum.com /printthread.php?t=8552&page=49&pp=40   (3558 words)

 Re: two questions for Uncle Al
But at least one experiment has claimed to have seen particles boyond the GZK limit.
It is not clear at the moment that there is anything to explain.
One of the two main experimental groups (AGASA) reported as of over a year ago that their high energy data are in accord with the expected GZK cutoff.
www.lns.cornell.edu /spr/2004-06/msg0061546.html   (761 words)

 Twin Paradox: Definitive Proof That It's SR? - Page 65 - Bad Astronomy and Universe Today Forum
Einstein’s theory creates a “paradox”, because the other observer can see YOUR clock as the one that “really slows down”, so when you and the other clock unite, the other observer sees your clock as “lagging behind” his, while you see his clock “lagging behind” yours, and this is an impossibility.
That’s why he was laughed at by physicists all over Europe, until he changed his theory with a correction in 1918.
The theory was postulated as an explanation of the effect of high energy cosmic rays which are observed to violate the "Greisen-Zatsepin-Kuzmin limit." (Known as the "GZK paradox.")
www.bautforum.com /showthread.php?p=173445   (2912 words)

 13 things that do not make sense - fundamentals - 19 March 2005 - New Scientist
Einstein's special theory of relativity dictates that any cosmic rays reaching Earth from a source outside our galaxy will have suffered so many energy-shedding collisions that their maximum possible energy is 5 × 10
His special theory of relativity says that space is the same in all directions, but what if particles found it easier to move in certain directions?
Then the cosmic rays could retain more of their energy, allowing them to beat the GZK limit.
www.newscientist.com /channel/fundamentals/mg18524911.600   (4106 words)

 Black Holes - Interview with Jonathan L. Feng
In addition to more typical research directions in theoretical particle physics, I had been thinking about cosmic rays for some time.
The original motivation was completely different—it was the GZK paradox, a puzzle involving the highest energy cosmic rays.
Later, however, Al Shapere and I began hearing that people were exploring the idea that, if there are large extra dimensions, fl holes could be created in future high-energy colliders.
www.esi-topics.com /blackholes/interviews/JonathanLFeng.html   (910 words)

 Astro-ph for busy people   (Site not responding. Last check: 2007-10-13)
This relation demands that BHs have unique mass M=0 (along with a=0) which in turn confirms that there cannot be any trapped surface in realistic gravitational collapse where the fluid has real pressure and density.
Since there is no trapped surface and no horizon there is no Information Paradox in the first place.
Comments: Paper presented at the CRIS 2004 Cosmic Ray Conference on "GZK and Surroundings", to be published in Nucl.
www.camk.edu.pl /~gwar/astro-ph/2004.08.19.html   (5306 words)

 Paradoxes Resolved, Origins Illuminated
A PARADOX exists that causes Time then to flow in two directions and in fact nothing at all could exist in UNIVERSE if this separation between the two directions of motion did not allow for the creational differentiation of mass formation to take place.
Further, a paradox of time exists between scales, the slower the speed of light the faster the rate of time in comparison to the apex dimensional scale where speeds of light would far exceed our standard light speeds.
It would have many irresolvable paradoxes if it were.
www.metaresearch.org /msgboard/post.asp?method=ReplyQuote&REPLY_ID=10928&TOPIC_ID=708&FORUM_ID=5   (12382 words)

Paradoxically, instead of a cutoff, more cosmic rays are observed above this energy than extrapolation from lower energies would predict.
The only plausible resolution of this paradox is the assumption that these UHE particles are being produced relatively close to the Earth, within about 160 million light years, which would place their source within the Local Group, i.e., in our galaxy or one of our near galactic neighbors.
Yet there are no known objects in the Local Group that might produce such energetic particles.
www.npl.washington.edu /av/altvw96.html   (2331 words)

 Interesting preprints
GZK Photons as Ultra High Energy Cosmic Rays
GZK cutoff distortion due to the energy error distribution shape
Seminar on Cosmic Rays: "GZK and Surroundings", to be published in Nucl.
www.physics.adelaide.edu.au /~gthornto/Abstracts/auger.html   (5302 words)

 Open Questions in Physics
The puzzle is especially acute because because particles with energies like these are expected to interact with the cosmic microwave background radiation and lose energy after travelling only moderate extragalactic distances, say 100 mega light years.
This effect is called the Greisen-Zatsepin-Kuz'min (or GZK) cutoff.
So, either our understanding of the GZK cutoff is mistaken, or ultra-high-energy cosmic rays come from relatively nearby--in cosmological terms, that is.
math.ucr.edu /home/baez/physics/General/open_questions.html   (7294 words)

 Physics 675, Fall 2004
These notes are only intended to indicate what was covered in class, and occasionally to include some extra info.
However, the Ricci tensor and metric both have ten independent components, so it seems as if the field equations are enough in number to determine the evolution of everything.
the resolution of this paradox is that not all ten of the field equations involve second order time derivatives.
www.physics.umd.edu /grt/taj/675c/675anotesR.html   (10099 words)

 Dialogos of Eide: 08/05
This limit was computed in 1966 by Kenneth Greisen, Vadem Kuzmin and Georgi Zatsepin, based on interactions predicted between the cosmic ray and the photons of the cosmic microwave background radiation.
Therefore, extragalactic cosmic rays with energies greater than this threshold energy should never be observed on Earth.
Anyway, this was brought up and the questioned asked, because I did understand something that even if it was based on theoretical definitions might have been ones that were different from another, and brought the scorn of high energy physicists to wonder, where such principles had been raised in terms of quantum gravity?
eskesthai.blogspot.com /2005_08_01_eskesthai_archive.html   (9946 words)

 RE: =AQ= Meet the Mods ~+Katy Kat+~ Awake in the land of dreams (online)
The fact that if you go after happiness itself you will be unhappy, but if you go for another goal you are likely to be happy.
The Greisen-Zatsepin-Kuzmin limit paradox (aka cosmic ray paradox) is when extragal
e seen on Earth, which according to GZK theory should not be happening.
forums2.battleon.com /f/tm.asp?m=2091929&mpage=3   (5282 words)

 RMCybernetics - Unexplained Phenomenon
What can this tell us about quantum gravity and general relativity?
GZK paradox: Why is it that some cosmic rays appear to possess energies that are impossibly high, given that there are no sufficiently energetic cosmic ray sources near the Earth, and cosmic rays emitted by distant sources should have been absorbed by the cosmic microwave background radiation?
High-temperature superconductors: Why do certain materials exhibit superconductivity at temperatures much higher than around 50 kelvins?
www.rmcybernetics.com /science/physics/unexplained.htm   (1449 words)

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